gko::experimental::distributed::preconditioner::Schwarz< ValueType, LocalIndexType, GlobalIndexType > Class Template Reference

A Schwarz preconditioner is a simple domain decomposition preconditioner that generalizes the Block Jacobi preconditioner, incorporating options for different local subdomain solvers and overlaps between the subdomains. More...

#include <ginkgo/core/distributed/preconditioner/schwarz.hpp>

Inheritance diagram for gko::experimental::distributed::preconditioner::Schwarz< ValueType, LocalIndexType, GlobalIndexType >:

Collaboration diagram for gko::experimental::distributed::preconditioner::Schwarz< ValueType, LocalIndexType, GlobalIndexType >:

Classes
struct	parameters_type
class	Factory

Public Types
using	value_type = ValueType
using	index_type = GlobalIndexType
using	local_index_type = LocalIndexType
using	global_index_type = GlobalIndexType
Public Types inherited from gko::EnablePolymorphicAssignment< Schwarz< default_precision, int32, int64 > >
using	result_type

Public Member Functions
bool	apply_uses_initial_guess () const override
	Return whether the local solvers use the data in x as an initial guess.
const parameters_type &	get_parameters () const
Public Member Functions inherited from gko::EnableLinOp< Schwarz< default_precision, int32, int64 > >
const Schwarz< default_precision, int32, int64 > *	apply (ptr_param< const LinOp > b, ptr_param< LinOp > x) const
Public Member Functions inherited from gko::EnablePolymorphicAssignment< Schwarz< default_precision, int32, int64 > >
void	convert_to (result_type *result) const override
void	move_to (result_type *result) override

Static Public Member Functions
static auto	build () -> decltype(Factory::create())
static parameters_type	parse (const config::pnode &config, const config::registry &context, const config::type_descriptor &td_for_child=config::make_type_descriptor< ValueType, LocalIndexType, GlobalIndexType >())
	Create the parameters from the property_tree.

Friends
class	EnableLinOp< Schwarz >
class	EnablePolymorphicObject< Schwarz, LinOp >

Detailed Description

template<typename ValueType = default_precision, typename LocalIndexType = int32, typename GlobalIndexType = int64>
class gko::experimental::distributed::preconditioner::Schwarz< ValueType, LocalIndexType, GlobalIndexType >

A Schwarz preconditioner is a simple domain decomposition preconditioner that generalizes the Block Jacobi preconditioner, incorporating options for different local subdomain solvers and overlaps between the subdomains.

A L1 smoother variant is also available, which updates the local matrix with the sums of the non-local matrix row sums.

See Iterative Methods for Sparse Linear Systems (Y. Saad) for a general treatment and variations of the method.

A Two-level variant is also available. To enable two-level preconditioning, you need to specify a LinOpFactory that can generate a multigrid::MultigridLevel and a solver for the coarse level solution. Currently, only additive coarse correction is supported with an optional weighting between the local and the coarse solutions, for cases when the coarse solutions might tend to overcorrect.

• See Smith, Bjorstad, Gropp, Domain Decomposition, 1996, Cambridge University Press.

Note

Currently overlap is not supported (TODO).

Template Parameters

ValueType	precision of matrix element
LocalIndexType	local integer type of the matrix
GlobalIndexType	global integer type of the matrix

Member Function Documentation

apply_uses_initial_guess()

template<typename ValueType = default_precision, typename LocalIndexType = int32, typename GlobalIndexType = int64>

bool gko::experimental::distributed::preconditioner::Schwarz< ValueType, LocalIndexType, GlobalIndexType >::apply_uses_initial_guess ( ) const

override

Return whether the local solvers use the data in x as an initial guess.

Returns

true when the local solvers use the data in x as an initial guess. otherwise, false.

Note

TODO: after adding refining step, need to revisit this.

parse()

template<typename ValueType = default_precision, typename LocalIndexType = int32, typename GlobalIndexType = int64>

parameters_type gko::experimental::distributed::preconditioner::Schwarz< ValueType, LocalIndexType, GlobalIndexType >::parse ( const config::pnode & config, const config::registry & context, const config::type_descriptor & td_for_child = config::make_type_descriptor< ValueType, LocalIndexType, GlobalIndexType >() )

static

Create the parameters from the property_tree.

Because this is directly tied to the specific type, the value/index type settings within config are ignored and type_descriptor is only used for children objects.

Parameters

config	the property tree for setting
context	the registry
td_for_child	the type descriptor for children objects. The default uses the value/local/global index type of this class.

Returns

parameters

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The documentation for this class was generated from the following file:

• ginkgo/core/distributed/preconditioner/schwarz.hpp